Method of increasing the cooling effect of a rotary kiln-satellite cooler and device for carrying out the method

ABSTRACT

Method of increasing the cooling effect of a rotary kilnsatellite cooler includes periodically injecting a cooling liquid from stationary nozzles, in synchronism with the rotary speed of the rotary kiln into the interior of the satellite tubes of the cooler through cooling air inlets formed at an end of the satellite tubes; and device for carrying out the method includes at least one cooling liquid supply line, at least one nozzle connected thereto and adapted to discharge a liquid jet having an axis spaced from the axis of rotation of the rotary kiln substantially equal to the spacing of the central axis of the satellite tubes therefrom, the nozzle having an outlet spaced slightly from the plane of rotation of air inlet ends of the satellite tubes, and at least one periodically operable valve connected to the liquid supply line.

United States Patent [1 1 Brachthauser et al.

[111 3,824,069 1 July 16,1974

[75] Inventors: Kunibert Brachthauser, Bensberg; Jurgen Langmaack, Niederkassel, both of Germany [73] Assignee: Klockner-Humboldt-Deutz Aktiengesellschaft, Cologne. G ermany 221 Filed: Mar. 9, 1973 [21] Appl. No.2 339,582

[30] Foreign Application Priority Data UNITED STATES PATENTS 1,379,083 5/1921 Clevenger 432/80 2,136,174 11/1938 Vogel-Jorgensen 432/106 X 2,483,738 10/1949 Petersen 432/80 3,512,764 5/1970 Jensen 432/80 Primary Examiner lohn Camby Attorney, Agent, or Firm-Herbert L. Lerner 5 7] ABSTRACT Method of increasing the cooling effect of a rotary kiln-satellite cooler includes, periodically injecting a cooling liquid from stationary nozzles, in synchronism with the rotary speed of the rotary kiln into the interior of the satellite tubes of the cooler through cooling air inlets formed at an end of the satellite tubes; and device for carrying out the method includes at least one cooling liquid supply line, at least one nozzle connected thereto and adapted to discharge a liquid jet having an axis spaced from the axis of rotation of the rotary kiln substantially equal to the spacing of the central axis of the satellite tubes therefrom, the nozzle having an outlet spaced slightly from the plane of rotation of air inlet ends of the satellite tubes, and at least one periodically operable valve connected to the liquid supply line.

15 Claims, 2 Drawing Figures PATENTED JUU 6 974 SHEU 2 BF 2 METHOD OF INCREASING THE COOLING EFFECT OF A ROTARY KILN-SATELLITE COOLER AND DEVICE FOR CARRYING OUT THE METHOD The invention relates to a method of increasing the cooling effect of a rotary kiln-satellite cooler and a device for carrying out the method.

Satellite coolers for rotary kilns are formed of several satellite tubes are disposed in the vicinity of the discharge end of the rotary kiln, uniformly distributed about the periphery of the rotary kiln, and are connected with the interior of the rotary kiln through communicating openings. The satellite tubes have as their objective the division of the flow of material discharging from the rotary kiln into several partial flows having correspondingly increased surface so that the material traversing the satellite tubes is cooled in counter-flow by cold air flowing into the discharge end of the satellite tubes due to the draught. The air which is thereby heated finally enters the rotary kiln through the communicating openings, and serves as preheated combustion air for the rotary kiln furnace. The quantity of air available for cooling is consequently limited so that, especially for relatively large kiln units, it can happen that cooled material discharging from the satellite tubes still has too high a temperature for the subsequent after-treatment. g

It has been known heretofore, with respect to rotary kilns which operate with so-called feed grid coolers, to dispose in the stationary cooler housing several nozzles through which water is sprayed on the layer of material to intensify the colling effect. Such a measure, that is spraying the material to be cooled with water through stationary nozzles, is not readily possible with satellite tubes which revolve with the rotary kiln.

It is an object of the invention to provide a method and device which increases the cooling effect of a rotary kiln'satellite cooler by spraying a cooling liquid, ordinarily, water.

With the foregoing and other objects in view, there is provided, in accordance with the invention, a method of increasing the cooling effect of a rotary kiln-satellite cooler which comprises periodically injecting a cooling liquid, preferably water, from stationary nozzles, in synchronism with the rotary speed of the rotary kiln, into the interior of the satellite tubes of the cooler through cooling air inlets formed at an end of the satellite tubes. Through this measure, it is possible to spray water by means of stationary nozzles on the layer of material to be cooled which is in the satellite tubes that revolve with the rotary kiln, and in fact so that the entire quantity of injected water within the satellite tubes vaporizes without impairing the environment.

In accordance with another mode of the method of the invention, the cooling liquid is simultaneously sprayed into a respective part of the satellite tubes that are located opposite one another with respect to or on either side of the axis of the rotary kiln. By this measure, the respective satellite tubes which project into the combustion chamber of the rotary kiln are traversed by a gas flow, varying as a result of the water injection, that is introduced substantially symmetrically into the rotary kiln, so that no disadvantageous effects are produced on the guidance of the rotary kiln flame and the flow relationships of the air or gas in the vicinity of the junctions of the satellite tubes with the rotary kiln.

In accordance with a further mode of the method of the invention, the cooling liquid is supplied to the individual nozzles through a common pressurized liquid supply manifold or collecting chamber. By this measure, assurance is provided that, for all simultaneously operating nozzles, substantially the same initial or prior pressure is applied to the liquid and, accordingly, especially the quantity of liquid that is to be'accelerated is substantially the same for each of the simultaneously operating nozzles, so that substantially the same quan* tity of liquid issues from all of the nozzles, respectively, at the same instant of time.

In accordance with yet another mode of the method of the invention the cooling liquid is injected, respectively at an instant and for a period of time which is dependent or contingent uponthe rotary speed of the rotary kiln. This measure has the advantage that the water injection is automatically adjusted or accommodated as to timing when changes in the rotary speed of the kiln occur.

In accordance with the invention, there is also provided a device for carrying out the foregoing method of increasing the cooling effect of a rotary kiln-satellite cooler wherein the satellite cooler includes satellite tubes respectively having an air inlet end at which an axially directed air inlet opening is located, that comprises at least one cooling liquid supply line, at least one nozzle connected to the liquid supply line and adapted to discharge a liquid jet having an axis spaced from the axis of rotation of the rotary kiln substantially equal to the spacing of the-central axis of the satellite tubes therefrom, the nozzle having an outlet spaced slightly from the plane of rotation of the air inlet ends of the satellite tubes and at least one periodically operable valve connectedto the liquid supply line. This construction of the device of the invention permits the injection instant and the injection period to be accurately determined especially for a suitable control device for the actuation of the valve, so that the liquid exclusively enters the interior space of the satellite tube and engages the layer of material therein which is to be cooled.

In accordance with an added feature of the device of the invention, the liquid supply line extends substantially circularaly with reference to or coaxially with the kiln axis, and a multiplicity of nozzles is disposed at spaced locations along the length of the liquid supply line, and a multiplicity of valves is respectively connected between the nozzles and the liquid supply line. This construction of the device of the invention permits all or only individual valves or valve groups to be actuated through a suitable control system for the valves, the delay of the injecting or spraying operation due to the required acceleration of the quantities of liquid can be maintained substantially equal for all of the nozzles due to the substantially ring-shaped or circular liquid supply line which serves as an initially pressurized liquid manifold or collecting chamber. With suitable dimensioning of the liquid volume contained in the supply line and with a suitably high pressure in this supply line, the acceleration process is capable of being considerably shortened.

In accordance with an added feature of the device of the invention, there are provided pump means having a pressure side and a suction side, the liquid supply line being connected to the'pressure side of the pump means and forming part of a circulatory loop, the circulatory loop having a' downstream end connected through the intermediary of a pressure-reducing valve with the suction side of the pump means. This feature of the invention affords continuous maintenance of liquid flow in the liquid supply line with the aid of the pump means, so that the acceleration of the liquid when the valves are opened is considerably decreased in the vicinity of the individual nozzles and the delay in the injection process can thus be markedly reduced.

In accordance with a concomitant feature of the invention, there is provided a control device, the valve having a preferably electrically or electromagnetically operative drive connected to the control device and one or more preferably electrically or electromagnetically operative pulse transmitters operatively associated with the rotary kiln and connected to the control device for transmitting pulses thereto. This construction of the device of theinvention provides an automatic adjustment or matching of the injection instant and injection period to the rotary speed of the rotary kiln.

' Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in method of increasing the cooling effect of a rotary kiln-satellite cooler and device for carrying out the method, it is nevertheless not intended to be limited to the details shown, since various modifications may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The invention, however, together with additional objects and advantages thereof will be best understood from the following description when read in connection with the accompanying drawings, in which:

F lGfl is a diagrammatic, fragmentary longitudinal sectional view of a rotary kiln with a satellite cooler constructed in accordance with the invention; and

FIG. 2 is a cross-sectional view of FIG. 1 taken along the line lllI in the direction of the arrows showing a preferred disposition of the supply line for the satellite cooler.

Referring now to the drawing and first, particularly, to FIG. 1 thereof, there is shown therein a rotary kiln structure which includes a rotary kiln 1 provided with an extension 2 in the material discharge region of the kiln 1, so that both the discharge region as well as the extension 2 are respectively supported by races 3 and 4 on roller stations. Communication or passageway openings 5 are provided in the kiln wall in the discharge region of the rotary kiln 1, satellite tubes 7 being connected by means of a transfer pipe 6 to the openings 5. The satellite tubes 7 are supported on the extension 2 and lead with the discharge end thereof into a discharge housing 8.

Because of this rotary kiln construction, the following mode of. operation of the satellite cooler results: The material to be cooledemerges from the rotary kiln 1 through the passageway openings 5 and enters respectively into the satellite tubes that happen to be located in the lower position thereof. Since hot kiln material isin this manner always admitted into the individual satellite tubes, a closed layer of material forms in each satellite tube, and runs through the satellite tube in the direction toward the discharge end due to the rotation of the kiln with continuous rolling around and piling up of the material by means of lifting buckets.

The discharge end of each satellite tube is constructed so thatthe cooled kiln material can fall into the discharge housing 8 through a discharge grating 9 secured to the satellite tube 7. Due to the kiln draft, the cooling air is admitted into each satellite tube 7 through a respective axially-directed air inlet opening 10 located at the discharge end of the rotary kiln 1. Cooling of the material occurs due to the air which sweeps over the surface of the material.

The sucked-in quantity of cooling air is limited because it corresponds substantially to the amount of required combustion air and depends upon the rotary speed adjustment of the exhaust gas blower afterconnected to the rotary kiln, and which is in induced draft operation. For this reason, the hot kilnmaterial is able to be cooled only to temperatures that are still for further transfer, for a possible intermediate storage, and the like.

ln accordance with the invention, the cooling effect of such a satellite cooler is intensified in that, depending upon the height of the desired ultimate temperature of the material, in addition to the cold air admitted into the satellite tubes, water is sprayed onto the layer of material present in the satellite tubes so that additional quantities of heat are withdrawn from the material through the required heat of vaporization. Due to the fact that both at the inlet end as well as at the outlet or discharge end of the rotary kiln, the end faces of the kiln are not readily accessible, especially because of the races connected to the kiln jacket or casing in the vicinity of the satellite cooler, it is virtually impossible to dispose forward of the air inlet openings injection nozzles that are firmly connected'to the rotary kiln jacket or casing and consequently revolve therewith, together with correspondingly revolving supply tubes. In order to permit the water injection, nevertheless, in accordance with the illustrated embodiment of the invention, a supply line 11 substantially annularly surrounding the rotary kiln 1 is disposed in the vicinity of the discharge housing 8 at the end face forward of the discharge or outlet ends of the satellite tubes 8. As shown in FIG. 2, one end of the supply line 11 is connected to the pressure side of a pump 12, while the other end thereof is connected through a pressure-reducing valve 13 to the suction side of the pump 12. Several nozzles 14 (FIG. 1) are connected through the intermediary of respective valves 15 to the annular supply line 11 so that the direction of the jets discharged from the nozzles 14 extends substantially in the axial direction of the satellite tubes. The number of the nozzles 14 depends upon the quantity of water necessary for cooling the material. The valves 15 are preferably magnetic valves, according to the invention, because the latter open and close rapidly, on the one hand, and from control engineering standpoint are relatively easy to actuate, on the other hand.

In this construction of the invention, the cooling liquid, usually water, is pumped through the supply line in the circulatory loop so that even when the nozzles 14 are closed, the water has a suitable flow velocity. The delay occurring when the valves 15 are opened, and which is caused by the required acceleration of the quantities of liquid in the supply line and in the branch lines to the nozzles 14, is thereby considerably reduced.

In this connection, it is advantageous for the branch lines to the nozzles 14, wherein, in the illustrated embodiment of the invention, the valves 15 are also installed, to be of minimum length. Instead of the illustrated pump 12, any desired water supplying device which produces adequate water pressure can be employed.

In order to be able to synchronize the instant of injection and the injection period accurately with the rotary speed of the kiln and thereby insure that the quantities of water to be injected are delivered only into the interior of the satellite tubes, in accordance with the invention, one or more pulse transmitters 16 are connected to the rotary kiln jacket or casing and cooperate with one or more pulse receivers 17. The pulse receiver or receivers 17 are connected to a control device 18, to which also control lines 19 to drives for the individual valves 15 are connected. Through the pulse transmitter 16, the rotary speed of the rotary kiln l and simultaneously also due to a corresponding disposition of other pulse transmitters on the jacket or casing of the rotary kiln 1, the respective geometric position of the satellite tubes is also registered. Through a suitable adjustment of the control device 18, in response to one or more pulses, the valves 15, such as magnetic valves, for example, connected forward of the nozzles 14, are briefly opened, the length of the period during which they are open being adjustable within specific limits through a suitable construction of the control device 18, which is obvious to any man of ordinary skill in the art.

Since the period during which the valves 15 are open is limited in accordance with the limited cross-section of the air inlet opening 10, on the one hand, and the relatively high revolving speed of the center of this opening 10, which can be for example, in the order of magnitude of 1.0 to 1.3 m/sec., on the other hand, several nozzles are closed simultaneously in groups, in accordance with the invention of the instant application, in order to improve the quantity control, so that when the control device 18 is suitably adjusted, the number of the operating nozzles 14 can be increased and reduced in groups. In this regard, it is advantageous that the nozzles 14 combined in groups oppose one another symmetrically with regard to the kiln axis so that the control of the gas flow, within the satellite tubes subjected to water, which proceeds through the passageway openings 5 into the kiln chamber, the control resulting from the vaporizing process, produces substantially symmetrical flow relationships within the kiln chamber in the vicinity of the furnace.

A further possibility for influencing or controlling the cooling effect is attained in an embodiment of the invention wherein the spacing between two respective adjacent nozzles 14, as viewed in rotary direction of the kiln 1, is smaller than the inner diameter of the air inlet openings of the satellite tubes 7. In such a compact nozzle arrangement, virtually a continuous water injection is capable of being achieved if the control device 18 controls the valves of the individual nozzles 14 through the pulse transmitters so that the open nozzle which happens to be located yet forward of the free cross section of the air inlet opening is closed when the next nozzle, as viewed in rotary direction of the kiln, happens to attain a position in front of the free cross section of the air inlet opening 10.

To improve the quantity control there is further provided, in accordance with the invention a step of measuring the total quantity of water that is to be injected, in dependence upon the final temperature of the material, after the material'has been discharged from the satellite tubes. This is effected, for example, with the aid of a temperature sensor 20 which is disposed in the kiln material flow in the vicinity of the outlet opening at the bottom of the discharge housing 8. The temperature sensor 20 emits a signal which is passed through a suitable transmitter 21 with a nominal value adjustment or comparison, and then to the control device 18. De-- pending upon the predetermined nominal temperature, the injection period of the individual nozzles 14 is then varied by the control device 18 and, to the extent that the injection period, with respect to the rotary speed of the kiln, is not to be increased any more, the number of the operating nozzles 14 is increased, the quantity of water delivered by each nozzle 14, during the opening or injection period thereof, being virtually determined by the known nozzle cross section and the assumed water pressure in the supply line 11.

In constructing the device of theinvention, it is furthermore expedient and advantageous to control, with the aid of thecontrol device 18, the water pressure prevailing in the supply line 11 in dependence upon the measured final temperature of the material in the discharge housing 8, in order to vary the through-put or flow-through quantity of the individual nozzles 14 and thereby the total quantity of water. This is attainable,

for example, through varying the rotary speed of the pump 12, as shown in FIG. 2, the drive motor 22 of the pump 12 being connected through a non-illustrated regulating device with the control device 18. This is especially of advantage when, in consideration of obtaining the most uniform cooling effect possible, the largest possible number of injection nozzles are provided, so that the injection, as aforementioned, occurs quasicontinuously. In this case, quantity regulation is primarily possible only through varying the prior or initial pressure of the liquid being injected and in limited scope through control of the injection period.

In the event the injection device can be connected to a water supply device having adequate prior or initial pressure, a control valve for controlling the total water quantity is substituted for the pump. This control valve can also be connected directly through suitable converters or transducers and control devices with the temperature sensor 20. The construction of the control device 18 is thereby simplified.

As mentioned hereinbefore, the invention of the instant application is not limited to the aforedescribed embodiment. In relatively simpler cases, it is sufficient, in accordance with the invention, to provide a simple supply line without any circulatory flow conduction of the water with suitably disposed nozzles, the simple supply line being merely connected with a suitable pressurized water supply device. Depending upon the quantity of water being injected, it can be sufficient to connect one valve in the supply line proper directly forward of the first nozzle, so that, upon opening this single nozzle, all of the nozzles are subjected to the supply of water. In such a case, it is sufficient for effecting quantity control, to furnish individual nozzles or nozzle groups with shut-off or check valves that are manually actuated. Instead of a single supply line, several separate supply lines, respectively, for groups of nozzles, can also be employed.

The invention of the instant application is furthermore not limited to the aforedescribed previously or initially pressurized supply of water, but rather, socalled two-substance nozzles are capable of being used in a similar manner, and can, for example, be subjected to compressed air as energy carrier so that when the valve is opened, a corresponding quantity of water is entrained by the compressed air and, respectively,

sprayed onto the hot layer of material in the satellite tubes.

We claim:

1. Method of increasing the cooling effect of a rotary kiln-satellite cooler which comprises the step of injecting a cooling liquid from stationary nozzles, in synchronism with the rotary speed of the rotary kiln, into the interior of the satellite tubes of the cooler through cooling air inlets formed at an end of the satellite tubes; and repeating the foregoing step periodically.

2. Method according to claim 1 which includes the step of simultaneously spraying the cooling liquid into arespective part of the satellite tubes that are located opposite one another'o'n either side of the axis of the rotary kiln.

3. Method according to claim 1 which comprises step of feeding the cooling liquid to the nozzles individually through a common pressurized liquid supply manifold.

4. Method according to claim 1 which comprises injecting the cooling liquid, respectively, at an instant and for a period dependent upon the rotary speed of the rotary kiln.

5. Method according to claim 1 which comprises the step of discharging from the satellite tubes material that has been processed in the rotary kiln, and the step measuring the total quantity of water to be sprayed into the satellite tubes contingent upon the final temperatures of the material processed in the rotary kiln after the material has been discharged from the satellite tubes.

6. Method according to claim 5 which comprises feeding the cooling liquid to individual nozzles through a common pressurized supply line, and the step of controlling the prevailing water pressure in the supply line contingent upon the final temperature of the material.

7. Device for carrying out a method of increasing the the satellite cooler includes satellite tubes respectively having an air inlet end at which an axially directed air inlet opening is located, comprising at least one cooling liquid supply line, at least one nozzle connected to said liquid supply line and adapted to discharge a liquid jet having an axis spaced from the axis of rotation of the rotary kiln substantially equal to the spacing of the central axis of said satellite tubes therefrom, said nozzle having amoutlet spaced slightly from the plane of rotation of the air inlet ends of said satellite tubes, and at least one periodically operable valve connected to said liquid supply line.

8. Device according to claim 7 wherein said liquid supply line extends substantially circularly with reference to said kiln axis, and including a multiplicity of nozzles disposed at spaced locations along the length of said liquid supply line and a multiplicity of valves respectively connected between said nozzles and said liq-f uid supply line. v

9. Device according to claim 7 including pump means having a pressure side and a suction side, said liquid supply line being connected to said pressure side of said pump means and forming part of a circulatory loop, said circulatory loop having a downstream end connected through the intermediary of a pressurereducing valve with the suction side of said pump means.

10. Device according to claim 7 wherein said valve is electrically actuable.

11. Device according to claim 7 wherein said valve is a magnetic valve.

12. Device according to claim 7, including a control device, said valve having a drive connected to said control device, and at least one pulse transmitter operatively associated with the rotary kiln and connected to said control device for transmitting a pulse thereto.

13. Device according to claim 12 wherein said valve drive and said pulse transmitter are electrically operative.

14. Device according to claim 12 wherein said valve drive and said pulse transmitter are electromagnetically operative.

15. Device according to claim 7 including a multiplicity of nozzles connected to said liquid supply line and spaced one from the other, the spacing between respective adjacent nozzles in rotary direction of the kiln being smaller than the inner diameter of the air inlet opening of said satellite tubes. 

1. Method of increasing the cooling effect of a rotary kilnsatellite cooler which comprises the step of injecting a cooling liquid from stationary nozzles, in synchronism with the rotary speed of the rotary kiln, into the interior of the satellite tubes of the cooler through cooling air inlets formed at an end of the satellite tubes; and repeating the foregoing step periodically.
 2. Method according to claim 1 which includes the step of simultaneously spraying the cooling liquid into a respective part of the satellite tubes that are located opposite one another on either side of the axis of the rotary kiln.
 3. Method according to claim 1 which comprises step of feeding the cooling liquid to the nozzles individually through a common pressurized liquid supply manifold.
 4. Method according to claim 1 which comprises injecting the cooling liquid, respectively, at an instant and for a period dependent upon the rotary speed of the rotary kiln.
 5. Method according to claim 1 which comprises the step of discharging from the satellite tubes material that has been proCessed in the rotary kiln, and the step measuring the total quantity of water to be sprayed into the satellite tubes contingent upon the final temperatures of the material processed in the rotary kiln after the material has been discharged from the satellite tubes.
 6. Method according to claim 5 which comprises feeding the cooling liquid to individual nozzles through a common pressurized supply line, and the step of controlling the prevailing water pressure in the supply line contingent upon the final temperature of the material.
 7. Device for carrying out a method of increasing the cooling effect of a rotary kiln-satellite cooler wherein the satellite cooler includes satellite tubes respectively having an air inlet end at which an axially directed air inlet opening is located, comprising at least one cooling liquid supply line, at least one nozzle connected to said liquid supply line and adapted to discharge a liquid jet having an axis spaced from the axis of rotation of the rotary kiln substantially equal to the spacing of the central axis of said satellite tubes therefrom, said nozzle having am outlet spaced slightly from the plane of rotation of the air inlet ends of said satellite tubes, and at least one periodically operable valve connected to said liquid supply line.
 8. Device according to claim 7 wherein said liquid supply line extends substantially circularly with reference to said kiln axis, and including a multiplicity of nozzles disposed at spaced locations along the length of said liquid supply line and a multiplicity of valves respectively connected between said nozzles and said liquid supply line.
 9. Device according to claim 7 including pump means having a pressure side and a suction side, said liquid supply line being connected to said pressure side of said pump means and forming part of a circulatory loop, said circulatory loop having a downstream end connected through the intermediary of a pressure-reducing valve with the suction side of said pump means.
 10. Device according to claim 7 wherein said valve is electrically actuable.
 11. Device according to claim 7 wherein said valve is a magnetic valve.
 12. Device according to claim 7, including a control device, said valve having a drive connected to said control device, and at least one pulse transmitter operatively associated with the rotary kiln and connected to said control device for transmitting a pulse thereto.
 13. Device according to claim 12 wherein said valve drive and said pulse transmitter are electrically operative.
 14. Device according to claim 12 wherein said valve drive and said pulse transmitter are electromagnetically operative.
 15. Device according to claim 7 including a multiplicity of nozzles connected to said liquid supply line and spaced one from the other, the spacing between respective adjacent nozzles in rotary direction of the kiln being smaller than the inner diameter of the air inlet opening of said satellite tubes. 